Chapter 38: The Promised Deliverer (Kitab Al-Mahdi)
Narrated Umm Salamah, Ummul Mu' minin: The Prophet (ﷺ) said: Disagreement will occur at the death of a caliph and a man of the people of Medina will come flying forth to Mecca. Some of the people of Mecca will come to him, bring him out against his will and swear allegiance to him between the Corner and the Maqam. An expeditionary force will then be sent against him from Syria but will be swallowed up in the desert between Mecca and Medina. When the people see that, the eminent saints of Syria and the best people of Iraq will come to him and swear allegiance to him between the Corner and the Maqam. Then there will arise a man of Quraysh whose maternal uncles belong to Kalb and send against them an expeditionary force which will be overcome by them, and that is the expedition of Kalb. Disappointed will be the one who does not receive the booty of Kalb. He will divide the property, and will govern the people by the Sunnah of their Prophet (ﷺ) and establish Islam on Earth. He will remain seven years, then die, and the Muslims will pray over him. Abu Dawud said: Some transmitted from Hisham "nine years" and some "seven years".
Sunan Abi Dawud 4286